Wrought-metal article.



EL'WOOD HAYNES, F. KOKOMO, INDIANA, ASSIGNOB. TO THE AMERICAN STAINLESS STEEL COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

- 1,299,4(Bd, Specification of Letters Patent.

Ho Drawing.

7 '0 all whom it may com-em Be it known that I, Enwoon Haynes, a

. citizen of the United States, residing at Koof which the following is a specification.

This invention relates to wrought metal articles; and it comprises wrought metal w articles of manufacture of the nature of cut-- lery and edged tools. such article having polished surfaces of the general character which is termed noble, in that such surfaces. are iucorrodihlc. lustrous and of permanent nature and such articles being composed of a worked down and hard body of an ironchromium alloy, low in carbon and in other metals, such alloy being stifi', strong and elastic, able to take and retains. cutting edge and having the other general properties of tempered metal; such as, forexalnple, an iron-chromium alloy containing not less than 8 per cent. chromium and, very advantageously, not less than 10 per cent, and not more than ,50 or 60 per cent, the best proportion of chromium being between 15 and '25 per cent, and containing not to exceed 1 per cent. of carbon (the amount of carbon being advantageously between 0.1 and 0.5 per cent.) with the rest of the alloy cons1sting mainly ofiron, there being no substantial amount, (say, not over 4: too per cent.) of other metals than iron and chromium in saidalloy; all as more fully hereinafter set forth and as claimed.

There. is a great demand in various arts for strong metals having a noble character,

that is, unattackable by corrosive agenciesg. g

that is for a metal or metallic material which will not tarnish. which shall be Workable and which will have a chamcter, like that of stifi' and strong steel being, for instance, capable of taking a cutting edge. It is desirable that such a material shall be capable of production on a commercial scale at a moderate cost and shall be capable of bein easily worked and manufactured, as by for mg, hammering, swaging or otherwise wor 'ng. It is further desirable that such a material shall be hard, tough. and elastic, with a capability of taking a high polish. The various noble metals, gold, silver, platinum, etc., aside from their cost, which is considerable, have no great strength of their own and are not suitable for any purpose where strength, stiffness, hardness, etc, are

requisite; as in making cutlery, evaporating pans, etc. The noble metals are often used as a liacmg 0r ornament for such, things as table knives, etc. as in plated ware, but of them-selves these metals are absolutely useless for cutting tools and the like. This need of a strong and stifi' metal having noble characteristics and suitable for cutting tools, I have heretofore met with certain alloys composed mainly of chromium and nickel and of chromium and cobalt (sec Patents 87 3,745 and 87 3,7 46). These alloys,'although consisting of two metals which in a separate .or pure state are more or less attackableby various reagents, are nevertheless,

Patented Apr. 1, 1919.

Application filed March 12 1916. Serial No. 18,92Q.

for all practical purposes, of absolutely noble character; they resist boiling in nitric acid,

they are unattacked by atmospheric influences, etc. In addition, they are so hard, strong and stifi as to enable, excellent implements to be made from them. These char,- acters they possessi-n such a'measure as to allow them to take and retain cutting edges. For example, the blade of a pocket lmife made of such a cobalt-chromium allo has excellent cutting properties, the edge ing smooth and ermanent. Such a knife blade is not fi'ecte by exposure to air, fruit acid etc. Its surface is as permanentas that o gold or platinum and more permanent under ordinary household conditions than that of silver.

I have found that I can produce alloys of i much the same character, although having somewhat difierent ropertiesin some respects, by uniting c romium and iron to ether in certain proportions to form what is, substantially, a binary alloy. The alloys so produced have, for all practical urposes, the same noble character as the alloys described and claimed in the Stated patents,

while they have certain specific advantages.

of their own. Amongfhese advantages is a. high degree of worka ility, that is, a malleability and ductilit at high metal working temperatures, say, tween a red heat an of-such alloys to be readily worked down into various forms for the production of wrought metal implements or articles. workability at h gh tem eratures is sufficicutly great to permit tli ture of such instruments as auger bits, chisels, table knives, etc. These alloys, being i an orange heat, which allows ingots or bars This e easy manufao eas es.

largely iron, are more readily united to iron and steel by welding and the like than is the case with the chromium-cobalt and chroloy containin around per cent. chrotill mlum is suite is for most of the pur oses hereinafter indicated. The amount 0' carbon in the 'alloy should not be higher than around 1 per cent; and it is better that it should be lower than this amount, say, around 0.1 to as per cent. in making the present alloy no other metals than chromium and iron should be present in substantial amounts, say, more than about a to 5 per cent. of the total alloy. .Howevor, additions or rather small amounts of other metals are occasionally advantageous for special pur exam is, in gra poses. For example, the presence of 2 to per cent. of molybdenum or off tun "sten, while not changing the character oit s all loy disedvantageously for most purposes, gives .t-it a somewhat diflerent luster and color; and for somepurposes this alteration in appearance is desirable. in order to secure an alloy of the type herein described, that is an alloy relatively bir h in chromium and low in carbon, s cia precautions must be taken. The ai 0 should not be made or melted in contact with carbon; that is, it should not be made, for yhite crucibles unless these cruci les are Wei lined with some indiderent material. Contact of chromium with carbon mustbe avoided since chromium has a at afinity forc'arbon, readilytorming car ids.

Proximity of carbon to or contact with the alloy during its manufacture is very disadvantageousp ltorthis reason, the use of graphite crucibles even if lined is disadvantageous. The best material for vessels for melting and formin%the alloy which I have found is alumina.

with a little kaolin as a binder issuitable.

' Electric heat or fire heat may be used tor melting. As a rule the comglonents that is the chromium and the iron, s ould be mixed air. After melting thezmixtur'e, which may bestirred, it should generally M allowed toremain in a molten state for a few mina chromium content of beor example, a; crucible composed of alundum or ignited, bauxite I chromium the alloy can be for under the hammer, shows no tendency to 8 utes to permit the mixture to quiet. There is little tendency to segregation or the for mation of non-hom eneous bodies of metal. After. formation an fusion it may be cast into any suitable mold to form ingots of any shape or size desired. It casts readily. The

ingots may be worked down in any suitable manner. Hammeringor swagmg' 1s a deslr- V able method.

The source and character of metals used for making the alloy is not a matter of indifierence. It is best to, use a good quality of metallic chromium as pure as may be. Ferrochrome cannot be used directly except with suflicient iron, suficiently free from carbon to'make the carbon content of the whole alloy average not to exceed thes'tated maximum of around 1 per cent.

Ferrov chrome runs from t to 12 percent. of carbon. in working with ferrochrome sub stantially carbonless iron must ordinarily be used. Pure carbon-free chromium made by the thermit process (reduction by aluminum) is suitable for the present pu oscs and may be used with iron containing a ittle carbon. -With pure chromium and with are low-carbon iron, it may even be desirah e at times in the melting operation to add a little carbon in order to prevent oxidationand to reduce o'sids present. @ther purifying ad ditions, however, such as a. little titanium or ferrotitanium, manganese, etc. are ordi naril better. A pure chromium-iron alloy suitable for the present purposes may be made'by treating commercial ferrochromium with a little oxid of chromium in the else tric furnace.

A good alloy under the present invention may be made by. uniting about 10 parts of chromium with garts of iron, the amount.

of carbon present inglll to 0.5 or cent.

This alloy is only attached to e si ht ex--.

tent by hot or boiling nitric acid. ts surface remains permanent under the action oi moisture, vegetable acids, air, etc. Such an alloy is malleable when heated and is canoble of being readily forged and worlred while hot, hardening on cooling. It will Mid ice

take a high polish and will receive and retain a good cutting edge- It can be united by'welding with; iron and steel with rather more readiness than the other alloys here inafter described having a higherchrommm content. I

ln this alloy as a rule I do not use more than 0.6 per cent. of. carbon. With as high as 0.6 per cent. of carbon'and mercent.

. readily crack inforging and is capable of to of carbon increases the, workability, diminishes somewhat and the metal becomes more inclined to crack." I regard 1 ner'cent. of

iso

carbon as a practical in this class of alloys although the percentage'may be raisedalloy rises above, so. 20 per cent, the danhon increases.

ger attendant on a igh proportion of car- Alloys of the type of those herein indicated containing as high as 50 per cent. chromium are well adapted for. non-corrodible cutlery, giving a very hard as well as tough metal, which will take a keen cutting edge; but alloys containing these high percentages of chromium are diflicult to work as compared with alloys containing a less amount, say, about to per cent.

As the percentage. 'of chromium in the alloy rises, and particularly with low amounts of carbon, the temperaturenecessary for fusion in the formation of the alloy increases. With alloys containing 40 Y per 'tageous cent. or more of chromium it is usuallv better to employ electric heating, as by the use of an electric arc.

Without materially modifying the advanroperties ofmy alloy as hereinbefore escribed I can incorporate amounts of other metals, and particularly of metals of the chromium group, such'as tung-' sten and molybdenum, say up to 4 or 5 per cent. In the case of tungsten and molybdenum, this, for some purposes, is advanta ous, since it gives a higher lusterto a go ished surface and somewhat difierent ut highly ornamental appearance. Small additions, say, up to 4 or 5 ercent. of nickel or cobalt may he used in t e same way and with similar results.

An alloy containing 20 to25 per cent. of chromium and 80 to 75 per cent. iron with 0.1 to 0.5 per cent. carbon is well adapted for the urposes of th' invention. Such an alloy is hard, stifi and stron has good elasticity, works'well under the ammer and swages readily, has a high luster, takingan excellent polish and will take and retain a furous smooth, ermanent cutting edge,-readi y renewable y honing orgrinding. The polish which can be given rivals that of silver while the metal is not tarnished or afiected by sulas is silver. This polish is practice y permanent against fruit acids, ex osure to air and rain, etc.

ile 1 regard my alloys as particularly adapted for t v similar articles, they may of course be used for any other purposes for which they are adapted. They may for example be used for the manufacture of standards of Wei hts and "measures, tools, bits, non-corr 1ble cooking utensils, etc. In sheet or late form they may be used for the manu acture- .of

evaporating pans and other chemical appaand retaining a cutting edge.

e manufacture of cutlery and ratus of large dimensions, their stifiness and strength well adapting them for this purpose. The alloys may of course be used as a facing layer for a body of iron or steel in making such ap aratus. Ingots of these alloys may be rea 11y drawn or rolled into rod, wire, sheet, etc. As previously stated, the

higher the percentage of chromium, as a rule, the higher are the working temperatures required in manufacturin the alloy and in working it into form. ith alloys containing less than about 20 per cent. of

chromium the incorrodi'bility is not quite as good as with alloys containing 20 per cent. or more of chromium. However with as little as 10 per cent. chromium the incorrodibility is sufiicient for many purposes. There is little advantage as regards nobleness of the increased dificulty in working. For this reason, I consider the alloys containing 20 to 25 per cent. chromium with 0.1 to 0.5 per cent. carbon as the .best adapted for the present purposes.

The present alloy is well adapted for mak: ing pen points for fountain pens, chisels, table knives, forks, and other purposes where hard metal of high temper is required.

What I claim 1s 1. A wrought metal tool having polished surfaces of the incorrodible characteristics of surfaces of noble metal and composed of an alloy of iron and chromium, with carbon in amount between 0.1 per cent. and 1.0 er cent, said alloy being malleable at hi h temperatures, hard, stifi' and strong at or inary temperatures and capable of taking 2. A wrought metal tool having polished surfaces of the incorrodilole character of p01- ished surfaces of noble metal and comprising an alloy containing from 8 er cent. to

.(iOper cent. of chromium and rom 40 per cent. to 92 per cent. ofiron, with carbon in amount between 0.1 per cent. and 1.0 per cent, said alloy being readily malleable and workable and being substantially free of other metals. 4

3. A wrought metal tool havin polished surfaces of the incorrodible charac r of polished surfaces of noble metal and compris-- ing an alloy of iron and chromium contain-' ing from 15' er cent. to 25 per cent. of chromium, an carbon in amount from 0.1 or cent. to 1.0 per cent, and being malcablc, ductile and elastic. 4. A wrought metal article having surieo 4, memeee faces of the inoorrodible character of sur- In testimony whereof, I e fix my signature faces of noble metal, and composed of an in the presence of two subscribing witnesses.

- alloy of iron andehromium, eontajnin car- ELWQOD HAYNES bon in amount of 0.1 per cent. to 1. per oent., said alloy being readily malleable end Witnesses:

' workable at high temperatures, and hard, H. R. PERRY,

stiff and strong at ordinary temperatures. R. CRAWFORD. 

